BIM practices in Estonia
Interviewees’ background
Two BIM experts were interviewed. The first BIM expert has over 10 years’ experience, international working background and now working locally in Estonia. The other BIM expert works as a BIM manager/coordinator for construction projects.
The use of BIM
BIM is commonly used in larger projects across various disciplines. The use of BIM is not dictated by the type of building but rather by the specific requirements of the project. Today, BIM is usually not used for private house designing.
From the preliminary design phase onwards, BIM is used in any larger project and often extends to the as-built model stage. For reconstruction projects, BIM models aren’t created if the reconstruction scope is rather small. For the reconstruction of unique and complex buildings, BIM is typically used.
Architectural design is modelled usually from the Schematic Phase and continues until the Technical Design Phase. Structural BIM modelling usually starts in the second half of the preliminary design phase by designing the main load-bearing systems. It gets more detailed in the following design stages (principal and operational building design phases). HVAC BIM design starts in the preliminary design phase by placing the main ducts for the ventilation system and shafts for the various communications. In the principal design phase, all of the main components of the HVAC system are modelled. Architecture mainly uses ArchiCad, Revit and Bently Microstation as BIM design tools. Structural engineers mainly use Revit or Tekla Structures. MEP designers use mainly Revit and MagiCAD, Cadmatic is main software for electricity and Autodesk Civil3d for infraBIM. IDA-ICE is also used for energy simulations.
Softwares such as BIMcollab Zoom, Solibri and Trimble Connect are most typically used to check the BIM models by comparing the various disciplines (Structural vs Architectural, HVAC vs Structural and so) for geometrical clashes, functionality errors and semantic content.
The most active local consortium in Estonia is Digital Construction Cluster, which has members across the construction sector, from material manufacturers to developers, including universities (Tallinn University of Technology, Tallinn Technical College, Estonian Academy of Arts). The cluster works with experts and authorities to advance digital construction and BIM through training and technology partnerships.
BIM guidelines
Separate organisations have their own internal guidelines for BIM use. Some have more detailed guidelines, while others are still developing theirs. Every project typically comes with a specific BIM Execution Plan, which outlines the rules for modelling. These plans and guidelines are generally created to meet ÜBN BIM requirements. The requirements are developed by the public sector in hand with the private sector. Estonian Centre for Standardisation and Accreditation (EVS) TK 50 (Technical Committee nr 50 - BIM) is responsible for maintaining and updating ÜBN requirements. Delegates from Ministry of Climate are also participating in that group and giving input especially regarding regulatory information requirements.
The specifications for level of development (LOD) and element data are described with ÜBN requirements. Level of geometry (LOG) is specified using BIM Forum guidelines.
It is planned that from the beginning of 2024, it will be possible to apply for the building permit by uploading the BIM model to EHR (Estonian Building Registry). If BIM-based building permit is selected, then models must be in open format (IFC) and meet ÜBN BIM requirements. However, there is no national BIM mandate for permitting processes or creating construction designs.
Naming conventions
In Estonia, there is no specific classification system used in projects today. CCI-EE is developed and covers, to some extent, materials as well, but still not in wide use as there is no requirement to do so. There are some forerunners like TalTech University and the Estonian Transport Administration.
In material type classification, structural engineers typically determine the materials and types for major building elements like walls, slabs, and roofs based on structural analysis. Architects usually follow these decisions. Architects primarily focus on selecting materials for the facade as well as the types and materials for openings.
ÜBN requirements do not have materials specified yet, but it is a work in progress, along with binding BIM data with CCI.
Quantity take-off
Design specifications (that include quantity take-offs) are done inside of the main authoring tools: ArchiCAD, Revit, Solibri, Trimble Connect, Tekla, SimpleBIM and others. For data transfer, an IFC format is used, as well as for handover delivery to the client. BCF format is used for model-based communication and issue management in a cloud environment (BIMcollab Server) and Trimble Connect also uses the cloud platform.
When it comes to BIM-based quantity take-off, often the problem lies in the underlying data. Still, also there are no clear rules for IFC export, and in some cases, there is a lack of skill among BIM practitioners on how to export IFC without losing any material data.